Apparatus for producing cement and similar substances



April 24, 1934.

K. E. E. HOLZAPFEL APPARATUS FOR PRODUCING CEMENT AND, SIMILARSUBSTANCES Filed May 27. 1930 2 Sheets-Sheet l INVENTOR 25ml ATTQRNEYApril Z4, 1934- K. E. E. HOLZAPFEL. 1,955,914 I APPARATUS FOR PRODUCINGCEMENT AND SIMILAR SUBSTANCES Filed May 27. 1930 2 Sheets-Sheet 2INVENTOR Patented` Apr. 24,v 1934 `UNITED STATES APPARATUS FOR PRODUCINGCEMENT AND SIMILAR SUBSTANCES Karl Emst Eberhardt Holzapfel, Munster,tiermany, assignor to Fried. Krupp Grusonwerk Aktiengesellschaft,Magdeburg-Buckau,

Ger-

many, a corporation of Germany Application May 27, 1930, Serial No.456,000

In GcrmanyJune 4, 1928 3 claims.

My invention relates to the production of ce-.Hv

ment and is adapted for general use in the manu-I facture of variouscalcined substances produced by a burning process, and the inventioncomprehends an improved apparatus or means peculiarly adapted forcarrying out said method.

An object of the invention is to combine a rotary kiln of known typewith a calcining shaft or pot. According to the invention, the shaft orpot l0 is of relatively small size, for 'the inventor has found that arelatively small column or layerof material makes the best economic useof the exhaust gases coming from the rotary kiln for the pre-heating'and preburning of the material. Fury (1) Touse a rotary kiln in serieswith a calcining shaft of relatively small height content,

so that the layer or column of material under calcination will belimited as to thickness or height and be maintained lsubstantiallyconstant. (2) To realize an embodiment in which the hot gases ofcombustion issuing from the feeding end of the kiln will be' drawnthrough a movingl layer of material of uniform thickness within thecalcining shaft. (3) To make possible an embodiment in which there isauniform or constant mass within the calcining'apparatus, which uniformor constant mass is conducive to steady calcination and oxidation, witha free and rapid escape of the volatile matter and carbonio acid. (4) Toenable maintenance at all times of substantial- `ly the same height ofmaterial in the calcining apparatus, the improvement in this regardinvolving the provision o'f an intermediate wall the mass of thematerial. (5) To realize the inwhich naturally commands the slope andhencetom of the material so that the gases will have to pass through thematerial and therefore lose much of theirl heat before reaching thegrate, thereby affording a protection for the grate.

Other objects and aspects of the invention will appear hereinafter.

Several embodiments of my invention are illustrated herein, the purposeand object of each of which are to illustrate by practical example theapplication of my method in general, and of selected apparatus throughthe agency of which to carry the invention into effect in a practicalway.

The principles of the invention andthe preferred modes of carrying thesame into effect in v a practical way will best be understood by re- '10 ferring to the accompanying drawings, forming a material part of thisapplication, and in whch:'

Figure 1 represents a View, in elevation and section, of an apparatusmade in accordance with my invention;

Fig. 2 represents a fragmentary vertical sectional view, showing amodied construction in which by reason of the arrangement of the wallsin the calcining apparatus a uniform quantity of material is deliveredfor treatment by a screw and the exhaust gases;

Fig. 3 is a vertical sectional view showing a further modificationwhereby the gases of combustion are caused to ilow from the top to thebottom of a moving uniform quantity of material within the calciningpot; and

Fig. 4 is a similar view of a still further modication, showing aninclined grate structure for feeding a moving uniform layer of materialforI treatment by the exhaust gases. p

' In carrying my invention into effect any suitable or approved furnacemay be employed, that shown, by way of example in Fig. 1, comprising alongitudinally inclined rotary shaft kiln 10-and an upright calciningshaft 11, which is of relat tively small height and which feeds directlyinto the rotary kiln at the feeding or elevated end thereof. 'I'he,rotary kiln has therein the usual sintering zone or chamber wherein thematerial under treatment is burned; while the shaft 11, 100 arranged insries with the kiln, provides a preheating or calcining chamber 11,'wherein the material is heated so as to expell the volatile matter andcarbonio acid. Arranged in the rear or discharge end of the rotary kilnis a burner apparatus 12 of any suitable or appropriate type, and bypreference of a type adapted to employ fuel consisting of any suitablecoal. For supplying the-burning apparatus with fuel, there is a supplyline 13 which leads from any suitable source 110 lli) of supply such asa hopper 14; and suitably associated with such supply line 13 is a rotoror blower device 15 vof any suitable or approved type adapted, underpressure, to supply the necessary combustion air along with the fuel fedto the burner 12.

According to an important feature of my invention, the calcining shaft11 is characterized by the fact that the pre-heating or calciningchamber 11 therein holds a layer or mass of material which is relativelysmall in 'height or thickness, and further by the fact that the bottomportion 16 of the shaft inclincs downwardly and rearwardly so that thematerial, as pre-heated or calcined, will be discharged directly intothe rotary kiln, and also so that the gases of combustion issuing fromthe rotary kiln, will pass directly through the discharging pre-heatedor calcined material and thence upwardly through the relatively smalllayer or mass of material undergoing pre-heating or calcination. In thepresent instance, the discharge. outlet from the calcining chamber isrepresented as comprising a neck or spout outlet 17 which enters intothe interior of the rotary kiln, the bottom of the spout consisting of adownwardly inclined continuation of the bottom 16 for thecalciningchamber l1. The front end 18 of the rotary kiln is closed withrespect to the delivery neck or spout 17 in order to prevent theentrance of air at this junction point. The closure means is representedas consisting of annular bushing or packing portions y19 between whichthe front end 18 has turning fit.

Connected with the upper portion of the calcining shaft 11 is an exhaustgas line 20, in which is incorporated a suitable fan or blower device 21for rapidly effecting the discharge of the gases. A downwardly inclinedconveyor device 22 is operatively arranged upon the downwardly inclinedbottom 16, such device being arranged to receive thereon material as itsettles downwardly in the calcining chamber 11' and to convey thematerial downwardly over the bottom to a point adjacent the rear end othe spout 17, where the material enters the rotary kiln. At the rear endof the conveyor, there is arranged within the delivery spout 17, astirring or discharging apparatus preferably consisting of a pluralityof curved vanes 23, which are carried by the rotary kiln. By theoperation of the stirring or discharging vanes 23 in conjunction withthe operation of the conveyor 22, the material is kept constantlytraveling from the calcining chamber 11 into the rotary kiln. Anadvantage of this arrangement is that the material is prevented fromIsticking and at the same time it is kept loose and in motion whereby toenable rapid travel of the combustion gases therethrough. Attention ishere called especially to the fact that under the instant arrangement,the rotary kiln is placed in series with a calcining shaft, the heightof which is-limited so that the 4 layer or mass of material therein willbe of small height or thickness. Under this arrangement, Jhere is nopronounced fluctuation in the layer or mass of material undergoing thecalcining process. Uniform calcination is, therefore, obtained, and inview of the conveyingand stirring devices associated with the outlet forthe calcining shaft, there is no sticking or accumulation of thematerial, the calcining operation is hastened and the output is,therefore, increased.

The raw material may be introduced into they calcining shaft by anysuitable or approvedl 'means, that herein shown consisting of a hopper24 and a feed screw 24a which conveys the material to the mixing screw24h where the material is moistened by water issuing from a water pipe24e. By mixing it with water, the material is formed in small bodies orcrumbs. The material falls from the mixing screw 24h into a chute 25having a pair of gate valves 25a which open downwardly so as to feed thematerial into the calcining shaft and -in a manner to avoid in so far aspossible the admission of air into the calcining shaft. Associated witheach of the gate valves 25a is an arm 25h weighted at 25o, wherebynormally to urge the valve to closed position. In order to maintain aconstantly uniform layer of material within the calcining shaft, adownwardly and outwardly inclined overflow pipe or channel 26a isprovided, and this pipe is equipped with weight operated gate valves 26esimilar to the gate valves 25a. IThe material passing through theoverflow pipe or channel 26a is taken up by a conveyor 26d forredelivery through the channel 26e into the chute 25. At the rear end ofthe rotary kiln, I may provide any suitable rotary cooling drum 26 forreceiving the clinkers as they fall from the rear or discharge end ofthe rotary kiln.

In the exemplication shown in Fig. 2, 27 designates the rotary kiln andthe upright calcining container or pot 28, which feeds into the rotarykiln through the spout 29, is divided intotwo parts 30 and 3l by avertical wall 32. The material to be pre-heated or calcined enters thetop of the part 30 through an air-tight feeding supply 33, equipped witha pair of weighted gate valves 33a similar to those hereinbeforedescribed. The lower end of the part 30 is open so that the materialwill falltherefrom to produce or tend to produce upon the bottom 34 acone-shaped mass or layer of material 35, through which the hot gases ofcombustion must pass in order to reach the part 31, with the top ofwhich is connected a gas outlet line 36. For drawing out the gases, asuction fan 36a is incorporated in the outlet line 36. Arranged abovethe bottom 34 is a screw 37 for discharging the material through thespout 29 into the rotary kiln. By this arrangement, the same thicknessof material is maintained at all times in the calcining pot, since theconeshaped mass naturally passing to the screw 37 upon the bottom 34tends always to constitute a determinate quantity. If desired, the wall32 may be made vertically adjustable in order to increase or decreasethe quantity of the cone-shaped mass tending to assemble upon the bottom34. As represented in the drawings, `the discharge screw 37 is shown asprovided in advance of the screw threads with a plurality of pins 37aadapted to stir the discharging material and whirl the same into a loosecondition. -The drying of the ma;- terial, the passage of the exhaustgases therethrough and the delivery of the material into the kiln arethus facilitated. Moreover, by the whirling action, the exhaust gasescome into contact with greatly increased surfaces of the material, acondition which is conducive to a rapid exchange of heat.

In Figs. 3 and 4, I have disclosed arrangements whereby the hot gases ofcombustion are guided downwardly from the top to the bottom of layers ofmaterial within the calcining pot. In the specific instance illustratedin Fig. 3, the combustion gases, in passing through the pot 38, arerequired to descend through the layer of material main.- tained constantand uniform by the wall or baille 39. The material `is supplied throughthe inlet 40 anda plunger device 41, arranged to operate with an outletchannel 54 for the gases.

across the downwardly inclined grate 42, serves as the instrumentalityfor 'feeding the material into the rotary kiln 43, the plunger deviceoperating in a path to push the material under the wall 39 for deliveryinto the kiln. After passing downwardly through the layer of material,the gases leave through the downwardly inclined grate 42 and escapethrough the smoke outlet 44.

In the particular form of construction illustrated in Fig. 4, thematerial is supplied bya feeding screw 45 into the chute 46 for deliveryonto the elevated end of a grate 47 made in the form of a descendingseries of steps, as shown, in order that a layer of material 48 willmove downwardly from the front wall 49 of the calcining pot to the rearwall 50 thereof. The hot gases of combustion leave the .feeding end ofthe rotary kiln 5l and enter the pre-heating chamber 52, thence beingdrawn or sucked downwardly through the relatively thin layer of movingmaterial 48 and through the grate 47 into the chamber 53 therebelow.Said chamber 53 is in communication At the rear end of the calciningpot, the material feeds into a pocket 55 in which a screw conveyer 55aoperates totransport continuously a certain amount of material from thelayer 48 to the elevator or conveyer 56, which in turn carries thematerial upwardly for delivery into a downwardly and forwardly inclinedchute 57 for delivery into the rotary kiln 51. The pocket 55 alwaysholds a definite quantity of material which ent-ers from the movinglayer 48 through a prescribed open 55h, but the `quantity of materialpassing through` the pocket 55 naturallyV depends upon the speed of thescrew 55a. These parts are proportioned and regulated so that always'aconstantly uniform quantity of material will be conveyed by the elevator56 to the chute 57 for delivery into the kiln. In this construction, thematerial within the calcining pot, as it travels slowlyl down thedescending grate 47, is spread into a relatively thin layer as shown, sothat the surfaces of the moving material are very considerably exposedlto the action of the hot gases of combustion. In this form ofconstruction, it is to be understood that the chute or supply pipe 45will constantly be kept full of material so as to exclude the outsideatmosphere without the use of gate valves such as illustrated anddescribed in connection with Figs, 1 and 2.

In all courses the material is preferably fed into the calcining potfinsuch condition that it will greatly facilitate the passing therethroughof the exhaust gases. For this purpose the material may be formed intobricks or into any suitable shape. Also, if desired, the material may bepre-heated in any customary or approved mannerand in granulated form,either a drum or a mixing screw of appropriately approved type beingused for handling or mixing the granulated material in this condition.

While I have described my invention as comlustrated it with the aid ofcertain selected forms for carrying it into eifect, it will beunderstood that the invention may be variously embodied. It has beensought herein to illustrate only such embodiments as will suice toexhibit the character of the invention. Reservation is, therefore, madeto the right and privilege of changing the form of detail set forth orotherwise altering the arrangement of the parts without departing fromhe spirit or scope of the invention or the scope of the appended claims.

I claim:-

1. In combination, a rotory kiln, a substantially horizontal feed shafthaving one end in communication with the kiln for discharging materialthereinto and receiving gas therefrom, separate compartments associatedwith the opposite end of the feed shaft, one for passing materialdownwardly into the feed shaft and the' other for receiving gas flowingthrough the feed shaft and material fed into the same, means forwithdrawthe feed shaft for' moving received material therethrough andinto the kiln, and a material stirring device associated with said screwadjacent the discharge end of the feed shaft.

2. In a kiln feeding device, a horizontally disposed feed shaft havingan outlet end adapted to be associated with a kiln to discharge'material thereinto and toreceive the combustion gases therefrom,mechanical means operating in the shaft for feeding material to theoutlet end for discharge from the latter, an inlet feed for the shaft,connected thereto from a lateral direction for supplying material to.the mechanical means and adapted to supply material to maintain asection of the shaft substantially filled crosssectionally with a massof material and during the operation of the mechanical means, and meansfor maintaining a continuous flow of the combustion gases reverselythrough the material being fed and the mass cross-sectionally fillingthe section of the shaft.

3. In a feeding device for kilns adapted to receive the hot' gases fromthe kiln for conditioning the material being fed, a feed shaft adaptedto be disposed horizontally and having an outlet end through which todischarge material and receive the gases, a suction chamber associatedwith the remote end of the shaft, means for drawing the gases from theoutlet end to said suction chamber, an inlet feed connected with theshaft from a lateral direction at a point between the outlet end andsuction chamber, operating means in the shaft for feeding material fromthe inlet feed to the outlet end for discharge from the latter andthrough the gases moving to the suction chamber, said inlet feed beingadapted to supply material to maintain a section of the shaftsubstantially filled cross-sectionally with a mass of material throughwhich the gases are required' to pass on their way to the suctionchamber.

KARL ERNST EBERHARDT HOLZAPFEL.

